You’re sleeping eight hours but still waking up exhausted. The culprit might be hiding in your blood, not your bed.

You're sleeping seven or eight hours. You're not pulling all-nighters. But when you wake up, you feel like you've been hit by a truck.

You've tried everything: better pillows, blackout curtains, no screens before bed. Nothing helps.

So you assume: "I just need more sleep."

But here's the tricky part... sometimes your exhaustion has nothing to do with sleep.

We're all trained to think: tired = need more sleep.

It's the obvious equation. And for some people, it's true.

But for millions of others, fatigue is coming from somewhere else entirely.

Your body stores iron in a protein called ferritin. Think of it as your iron battery.

When your ferritin runs low, your body struggles to make red blood cells efficiently. Red blood cells carry oxygen. No oxygen delivery = exhaustion, even if you're sleeping perfectly.

Your doctor might check your hemoglobin (the iron in your blood right now) and say it's "normal." But that doesn't tell you about your stored iron.

You can have "normal" hemoglobin and tanked ferritin. And that's when you feel like death while looking fine on paper.

Low ferritin has a signature. Look for the cluster:

Exhaustion that doesn't improve with rest. Hair loss or thinning. Shortness of breath when climbing stairs. Cold hands and feet. Brittle nails. Brain fog that coffee can't fix.

If you're nodding along, ferritin might be your culprit.

Standard annual physicals often skip ferritin. They check hemoglobin (to catch anemia), but storing iron and using iron are two different things.

Your hemoglobin could be fine while your storage is empty. Your doctor would give you a thumbs up. You'd go home and wonder why you feel like a zombie.

Here's the good news: ferritin responds to intervention.

Add one iron-rich meal per day. Red meat, shellfish, or even fortified cereals with vitamin C (which helps absorption).

But be patient. While you might feel a spark of energy sooner, medical literature suggests it typically takes 6–12 weeks to fully replenish your iron stores. It's not an overnight fix, but it is a lasting one.

Try this: For a few weeks, add one iron-rich food daily. Track how you feel. Do you have more energy? Do you stop needing that 3 PM coffee?

If yes, your ferritin was probably low. That's valuable information.

If no, then ferritin wasn't your issue, and you've narrowed down the puzzle.

The challenge is: you won't know your actual ferritin number without testing. You could be tired for seven different reasons. Low iron is just one.

That's where comprehensive blood work comes in.

InsideTracker tests ferritin alongside dozens of other markers, so you see the full picture of what's actually dragging down your energy.

It takes the guesswork out. Instead of trying random supplements and sleep hacks, you know exactly which biomarker is holding you back.

If you want to stop being tired and actually know why, check it out. Your future self will thank you.

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